Method of extruding life of copper anode molds

ABSTRACT

Copper anode molds excessively warped by normal use in anode casting wheels are machined internally of the mold cavity to remove interior deformation of the bottom of the mold cavity and restore planar flatness thereto. The wall portions that border the machined bottom area are reduced in height by machining or by replacement. The so-reconstructed molds are shimmed to normal level in the casting wheel and are reusable for approximately five times the normal life of a new mold.

United States Patent 1191 Peterson et al.

[ 1 Apr. 16, 1974 METHOD OF EXTRUDING LIFE OF COPPER ANODE MOLDS [76] Inventors: Robert H. Peterson, 2787 Lonedell Dr., Salt Lake City, Utah 84117; Richard L; Christiansen, 2606 Elm Ave., Salt Lake City, Utah 84109 22 Filed: Apr. 17,1972

21 Appl. N6; 244,811

52 US. 01 29/401, 164/6, 249/205 51 Int. Cl 823p 7/00 58 Field of Search 29/401, 402; 164/92, 342,

56 1 References Cited UNITED STATES PATENTS 3,142,114 7/1964 Zieger 29/402 2,799,067 7/1957 Peterson 164/342 X 2,004,081 6/1935 Ryan 29/401 X 3,220,101 l1/1965 Roy. 29/401 1,584,954 Lee et al 164/6 FOREIGN PATENTS OR APPLICATIONS 551,968 1/1958 Canada .1 164/6 Primary ExaminerCharles W. Lanham Assistant Examiner-D. C. Reiley, lll Attorney, Agent, or Firm-Philip A. Mallinckrodt [5 7] ABSTRACT Copper anode molds excessively warped by normal use in anode casting wheels are machined internally of the mold cavity to remove interior deformation of the bottom of the mold cavity and restore planar flatness thereto. The wall portions that border the machined bottom area are reduced in height by machining or by replacement. The so-reconstructed molds are shimmed to normal level in the casting wheel and are reusable for approximately five times the normal life of a new mold.

3 Claims, 4 Drawing Figures METHOD OF EXTRUDING LIFE OF COPPER ANODE MOLDS BACKGROUND OF THE INVENTION Field: The invention has to do with production of anode electrodes of impure metallic copper for use in electrolytically refining the impure copper, such electrode production being accomplished by casting molten impure copper into molds carried by a casting wheel or the like.

State of the Art: Fire refined copper or other form of impure metallic copper in a molten state is conventionally poured into shallow cavity molds of stripper anode type and of commerical anode type for the production, respectively of stripper and commercial types of anode electrodes, which are used in the electrorefining of such impure copper in electrolytic cells. The molds are usually carried on casting wheels or the like and arranged thereon as an endless series. Molten copper is poured directly into the molds sequentially from a casting ladle, a succeeding mold in the series moving into receiving position during the time the ladle is being refilled following the preceding pour. Cooling water in spray or mist form is then applied to the cast metal in the mold prior to the removal of the so-formed anode. Such anode molds are themselves normally made of copper and are subject to extensive warping over a period of use. When warpage has become so great that the anodes produced can no longer be used, without danger of causing short circuits during the usual first stage of electrorefining by reason of stripper anode deformation, or without serious interference with operating efficiency during the usual second stage of electrorefining by reason of abnormal lower end thinness of commerical anodes, the warped molds are normally melted and the resulting molten copper formed as new unwarped molds by using a mold press designed to give the desired anode configuration.

SUMMARY OF THE INVENTION In accordance with the present invention, the excessively warped'molds are not melted and made into new molds. Rather, it has been found that if they are subjected to a machining operation toremove deformation of and thereby flatten the mold cavity bottom and if wall portions bordering the machined areas are reduced in height as may be necessary to accommodate the anode casting facilities when the reconstructed anode molds are shimmed level on the casting wheel, such reconstructed molds will have a useful life far exceeding that of a new mold, usually five times as great.

THE DRAWING A typical anode mold in new, in excessively warped, and in reconstructed conditions, representing the best mode presently contemplated of carrying out the invention is illustrated in respective figures of the accompanying drawing, in which:

FIG. 1 is a top perspective view of a stripper anode mold in its usual new condition;

FIG. 2, an axial vertical section taken along the line 2-2 of FIG. 1, the mold being mounted on a casting wheel;

FIG. 3, a view corresponding to that of FIG. 2, but taken after the mold is excessively warped by use and is ready for conventional melting down to be recast in the form of a new and unwarped mold, the original configuration of the mold casting being indicated by dotted lines; and

FIG. 4, a view corresponding to those of FIGS. 2 and 3, but showing the same anode mold following reconstruction in accordance with the invention.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT The illustrated anode mold 10 is a typical, so-called stripper mold whose broadly open and relatively shallow mold cavity 11 is configurated to provide suspension-hanger-ear-forming portions 11a at one end thereof and a rectangular portion 11b extending from such portions 11a to the opposite end of the mold cavity. Such cavity 1 1 provides for the forming of an anode electrode (not shown) when molten impure copper is poured thereinto, which anode electrode has a rectan-v gular lower end and suspension hangers at its upper end. It is onto the rectangular portion 11b of the mold cavity, adjacent the said opposite end of such cavity, that the molten copper is poured into the mold, and it is this portion of the mold that is deformed by warping as shown in FIG. 3.

In use, the anode mold 10 is normally mounted on a conventional casting wheel 12 along with other similar anode molds that, together, form an endless, annular series. The individual molds are leveled on the wheel 12 by means of leveling screws 13 mounted in flanges of respective I-beams 14. The casting wheel rotates beneath a casting ladle (not shown), and cooling water in the form of spray or mist (not shown) is directed onto the metal pour in the mold as successive molds are filled with molten copper from the casting ladle and rotate into the line of action of such cooling water.

The mold 10 is provided with a push-up pin 15, which is fitted freely into a receiving hole 16 through the mold bottom for use in extracting the cast anodes from the mold following solidification and cooling thereof within the mold cavity.

All of the above is in accordance with standard practice.

As is customary in copper anode molds of both stripper and commerical types, the mold cavity 11 is broadly open and is shallow relative to the overall thickness of the mold itself. It is thus able to withstand the high temperature of the molten copper that is poured into the mold cavity. Typically, such a mold is 52 inches long, 45 inches wide along the rectangular portion 11b, and 12 inches thick. The mold cavity is 3 to 4 inches deep and is defined by side walls 16 and end walll7 which are typically 3 to 5 inches wide.

Despite the relatively great thickness of the mold bottom 18 upon which the molten copper is poured, considerable warping along and starting about midway of the length of the rectangular portion 11a of such mold bottom and the surrounding side and end walls occurs incrementally throughout the course of about l,370 individual pours, and at approximatelythis point the mold attains a seriously warped configuration somewhat as indicated in FIG. 3. Anode electrodes formed by such a warped mold are themselves warped and have relatively thin lower ends that tend to cant toward adjacent electrodes in an electrolytic cell, posing a real danger of short-circuiting stripper cells by reason of contact with such adjacent electrodes and, in commerical cells, of seriously interfering with proper operation.

When this condition of warpage of an anode mold is reached, it must be taken out of service and is normally melted down into molten copper that is formed into a new mold by use of a conventional mold press designed to give the desired anode configuration. Thus, the warped mold of FIG. 3 would normally be melted down and the molten copper therefrom formed into a new mold, such as shown in FIGS. 1 and 2.

In accordance with the present invention, the warped mold of FIG. 3v is machined, as by the use of a standard horizontal drill press, for the removal of warped metal 19, FIG. 3, from the mold cavity bottom 11c to restore planar flatness thereof, see FIGS. 2, 3 and 4. Portions 16a and 17a, FIG. 3 of the side walls 16 and end wall 17 that border the machined area 19 of the bottom of the mold cavity are also removed to reduce the wall height such that the metal casting facilities are accommodated and cleared by the so-reconstructed mold during rotation of the casting wheel on which it is mounted.

Reduction of wall height as explained above can be accomplished by machining in any effectivemanner or by a combination of machining and wall replacement in instances where available machining equipment, such as a planer, for flattening the bottom of the mold cavity requires that the end wall 17 also be completely removed. In the latter instance, a replacement end wall is cast or machined to shape and is secured in position in the reconstructed mold by bolts or other suitable means.

It has been found that a mold l0 reconstructed in this manner and mounted on a casting wheel in the usual manner, but with its position adjusted so that the new planar bottom 21, FIG. 4, of the mold cavity is level, will serve its intended purpose many times longer than will a new anode mold formed in the usual manner. Perhaps even more important than this is the fact that the reconstructed mold will no longer suffer incremental or other warpings which means that anode electrodes produced subsequently to the reconstruction of the mold will be fully and properly formed and will provide for maximum electrolytic cell efficiency and copper recovery in the tankhouse as compared with the usual incremental decrease in efficiency normally resulting from the use of anodes produced from new molds.

Thus, an anode mold reconstructed in accordance with the invention will ultimately serve approximatelyv five times as long as will a new anode mold and will promote increased tankhouse efficiency.

Whereas this invention is here illustrated and described in detail with respect to a preferred form thereof representing the best mode presently contemplated of carrying out the invention, various changes may be made without departing from what is claimed hereinafter.

We claim:

1. A method of multiplying the normal life of a copper anode mold and of promoting electrolytic tankhouse efficiency, said mold having a broadly open mold cavity which is shallow relative to the overall thickness of themold and which mold has become excessively warped by the repetitive casting and rapid coolingof molten copper in the mold cavity during use of the mold, comprising machining the bottom of the mold cavity of such an anode mold to remove interior deformation of such mold cavity bottom and to restore planar flatness'thereofj shimming the reconstructed mold to normal casting level; and producing copper anodes by use of said reconstructed mold.

2. A method in accordance with claim 1, wherein the height of wall portions of the mold that border the machined area of said mold cavity bottom are reduced in height to accommodate casting facilites.

3. A method in accordance with claim 1, wherein copper anodes produced by the reconstructed molds are installed in electroytic cells and used in the refining of the copper making up said anodes.

L. Christiensen inv i Robert H eertified' eorreetefi shown below:

and that said batters Patent the title, the word should be Extending in the address of inventor Robert H. Peterson, the word Lonedeii should be Loredeil Col, '1, lines and 35 and 2, lines 45 and 67, the Word commence-l" should be commercial Signed and sealed this 2 0th day of Sept ember- 'i 97h.

I n T Qmq Access GIBSON, JR. c. MARSHALL 'DANN Ac'sest ing Officer Commissioner of Patents and 

1. A method of multiplying the normal life of a copper anode mold and of promoting electrolytic tankhouse efficiency, said mold having a broadly open mold cavity which is shallow relative to the overall thickness of the mold and which mold has become excessively warped by the repetitive casting and rapid cooling of molten copper in the mold cavity during use of the mold, comprising machining the bottom of the mold cavity of such an anode mold to remove interior deformation of such mold cavity bottom and to restore planar flatness thereof; shimming the reconstructed mold to normal casting level; and producing copper anodes by use of said reconstructed mold.
 2. A method in accordance with claim 1, wherein the height of wall portions of the mold that border the machined area of said mold cavity bottom are reduced in height to accommodate casting facilites.
 3. A method in accordance with claim 1, wherein copper anodes produced by the reconstructed molds are installed in electroytic cells and used in the refining of the copper making up said anodes. 